It is
They each have a right angle and they share an angle (the one in the right corner)
This means that they share 2 angles and therefore share all angles
edit: pt2
[tex] \frac{x}{10+4} =\frac{3}{4} [/tex]
[tex] \frac{x}{14}(times2) = \frac{3}{4}(times7) [/tex]
[tex] \frac{2x}{28} = \frac{21}{28} [/tex]
2x = 21
x=10.5
[tex] \frac{y}{14}(times2)= \frac{5}{4}(times7)
[/tex]
[tex] \frac{2y}{28} = \frac{35}{28} [/tex]
2y=35
y=17.5
